Objective: To characterize animals with microchips entering animal shelters and the process used to find owners.
Design: Cross-sectional study.
Animals: 7,704 microchipped animals entering 53 animal shelters between August 2007 and March 2008.
Procedures: Data for animals with microchips were recorded by participating animal shelters and reported monthly.
Results: Of 7,704 animals, strays accounted for slightly more than half (4,083 [53.0%]), with the remainder classified as owner-relinquished animals (3,225 [41.9%]) and other (396 [5.1%]). Of 3,425 stray animals for which animal shelters reported that the owner was found, a higher percentage of dog owners (2,191/2,956 [74.1%]) than cat owners (298/469 [63.5%]) was found. For 876 animals for which the owners could not be found, the main reasons were incorrect or disconnected telephone number (310 [35.4%]), owner did not return telephone calls or respond to a letter (213 [24.3%]), and animal was registered to another group (151 [17.2%]). Of 1,943 animals for which animal shelters contacted a microchip registry, 1,129 (58.1%) were registered in the database. Purebred neutered dogs whose owner information was in the shelter database registry or microchip registry had a higher likelihood that the owners would be found.
Conclusions and clinical relevance: The high rate for return of microchipped dogs and cats to their owners supported microchipping as a valuable permanent pet identification modality; however, issues related to registration undermined its overall potential. Bundling of microchip implantation and registration, point-of-implantation data registration, use of annual compliance and update reminders, and providing access to all registries are potential solutions.